In the present study, we found that nanoparticles (Pd-NPs) were biosynthesized by Bacillus wiedmannii MSM ( B. wiedmannii MSM) with endogenous carbon under O 2 condition, and more favorablity under N 2 purging condition. XRD results indicated that crystal planes of Pd-NPs were attributed to Pd 0 (111), Pd 0 (200), Pd 0 (220), and Pd 0 (311), respectively. TEM and STEM-EDX results showed that the bio-reduction of Pd (II) ( k pd,1 =4.799 min −1 ) occurred predominately in periplasm space. FTIR results showed that the -COOH, -OH, and -NH 2 were the main groups participating in the removal of Pd (II). The aerobic reduction of Pd (II) by B. wiedmannii MSM was proposed, including extracellular superoxide radicals produced by NAD(P)H oxidases , endogenous electron donors, and O 2 -insensitive hydrogenase. These studies provide new methods and insights for reduction of Pd (II).
Yixuan Yang,Runliang Zhu,Qingze Chen,Haoyang Fu,Qiuzhi He,Jianxi Zhu,Hongping He
Multifunctional adsorbents based on montmorillonite (Mt) have been of highly concerns due to their unique 2D layer structures and impressive co-adsorption performances. To further enhance the support ability and reactivity, a strategy was developed in this study to enable the co-existence of porous nanosilica (PNS) and hydrophobic interlayer spaces in Mt structure, and a novel multifunctional adsorbent (iron modified-acidified organo-Mt, Fe-AOMt) was then synthesized, aiming to simultaneously remove hydrophobic contaminants , oxyanion contaminants and heavy metals in water. The combination of XRD , FTIR and TEM verified the co-existence of amorphous PNS and layered structure (containing intercalated surfactant) in the acidified organo-Mt (AOMt), and results of STEM-EDX revealed uniform distribution of Fe after the further introduction of Fe hydroxides to AOMt. Additionally, pore structure analyses suggested that the acid activation can obviously increase the pore volume and specific surface area of OMt. Batch adsorption experiments revealed that Fe-AOMt as a promising multifunctional adsorbent was able to effectively and simultaneously remove nitrobenzene , phosphate, and Cd(II) in the multi-contaminant system. The synergetic adsorption of phosphate and Cd(II) on Fe-AOMt suggested the formation of ternary surface complexes (≡Fe–P–Cd), while the pH-independent uptake of nitrobenzene was hardly influenced by adsorption of phosphate and Cd(II), implying dissimilar adsorption mechanisms. The co-adsorption mechanism on Fe-AOMt was further revealed via XPS . Our work provided a novel and efficient Mt-based multifunctional adsorbent with a newly-proposed structure, which was a preliminary exploration of diversifying locations and types of active sites in Mt structure.
危险品化学品经营许可证（带存储）